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Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]7<title>Customizing LLVMC: Reference Manual</title>
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10<body>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]11<div class="document" id="customizing-llvmc-reference-manual">
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]12<h1 class="title">Customizing LLVMC: Reference Manual</h1>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]13
Mikhail Glushenkove04b5bf2008-12-13 17:51:47 +0000[diff] [blame]14<!-- This file was automatically generated by rst2html.
15Please do not edit directly!
16The ReST source lives in the directory 'tools/llvmc/doc'. -->
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]17<div class="contents topic" id="contents">
18<p class="topic-title first">Contents</p>
Mikhail Glushenkovc0363fc2008-12-13 02:28:58 +0000[diff] [blame]19<ul class="simple">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]20<li><a class="reference internal" href="#introduction" id="id8">Introduction</a></li>
21<li><a class="reference internal" href="#compiling-with-llvmc" id="id9">Compiling with LLVMC</a></li>
22<li><a class="reference internal" href="#predefined-options" id="id10">Predefined options</a></li>
23<li><a class="reference internal" href="#compiling-llvmc-plugins" id="id11">Compiling LLVMC plugins</a></li>
24<li><a class="reference internal" href="#compiling-standalone-llvmc-based-drivers" id="id12">Compiling standalone LLVMC-based drivers</a></li>
25<li><a class="reference internal" href="#customizing-llvmc-the-compilation-graph" id="id13">Customizing LLVMC: the compilation graph</a></li>
26<li><a class="reference internal" href="#describing-options" id="id14">Describing options</a><ul>
27<li><a class="reference internal" href="#external-options" id="id15">External options</a></li>
Mikhail Glushenkovc0363fc2008-12-13 02:28:58 +0000[diff] [blame]28</ul>
29</li>
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]30<li><a class="reference internal" href="#conditional-evaluation" id="id16">Conditional evaluation</a></li>
31<li><a class="reference internal" href="#writing-a-tool-description" id="id17">Writing a tool description</a><ul>
32<li><a class="reference internal" href="#id5" id="id18">Actions</a></li>
Mikhail Glushenkovc0363fc2008-12-13 02:28:58 +0000[diff] [blame]33</ul>
34</li>
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]35<li><a class="reference internal" href="#language-map" id="id19">Language map</a></li>
36<li><a class="reference internal" href="#option-preprocessor" id="id20">Option preprocessor</a></li>
37<li><a class="reference internal" href="#more-advanced-topics" id="id21">More advanced topics</a><ul>
38<li><a class="reference internal" href="#hooks-and-environment-variables" id="id22">Hooks and environment variables</a></li>
39<li><a class="reference internal" href="#how-plugins-are-loaded" id="id23">How plugins are loaded</a></li>
40<li><a class="reference internal" href="#debugging" id="id24">Debugging</a></li>
41<li><a class="reference internal" href="#conditioning-on-the-executable-name" id="id25">Conditioning on the executable name</a></li>
Mikhail Glushenkovc0363fc2008-12-13 02:28:58 +0000[diff] [blame]42</ul>
43</li>
44</ul>
45</div>
46<div class="doc_author">
47<p>Written by <a href="mailto:foldr@codedgers.com">Mikhail Glushenkov</a></p>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]48</div><div class="section" id="introduction">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]49<h1><a class="toc-backref" href="#id8">Introduction</a></h1>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]50<p>LLVMC is a generic compiler driver, designed to be customizable and
51extensible. It plays the same role for LLVM as the <tt class="docutils literal"><span class="pre">gcc</span></tt> program
52does for GCC - LLVMC's job is essentially to transform a set of input
53files into a set of targets depending on configuration rules and user
54options. What makes LLVMC different is that these transformation rules
55are completely customizable - in fact, LLVMC knows nothing about the
56specifics of transformation (even the command-line options are mostly
57not hard-coded) and regards the transformation structure as an
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]58abstract graph. The structure of this graph is completely determined
59by plugins, which can be either statically or dynamically linked. This
60makes it possible to easily adapt LLVMC for other purposes - for
61example, as a build tool for game resources.</p>
Mikhail Glushenkov7af1d242009-06-17 02:56:48 +0000[diff] [blame]62<p>Because LLVMC employs <a class="reference external" href="http://llvm.org/docs/TableGenFundamentals.html">TableGen</a> as its configuration language, you
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]63need to be familiar with it to customize LLVMC.</p>
Reid Spencerd5c0ccb2004-08-09 03:08:29 +0000[diff] [blame]64</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]65<div class="section" id="compiling-with-llvmc">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]66<h1><a class="toc-backref" href="#id9">Compiling with LLVMC</a></h1>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]67<p>LLVMC tries hard to be as compatible with <tt class="docutils literal"><span class="pre">gcc</span></tt> as possible,
68although there are some small differences. Most of the time, however,
69you shouldn't be able to notice them:</p>
70<pre class="literal-block">
71$ # This works as expected:
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]72$ llvmc -O3 -Wall hello.cpp
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]73$ ./a.out
74hello
75</pre>
Mikhail Glushenkov7af1d242009-06-17 02:56:48 +0000[diff] [blame]76<p>One nice feature of LLVMC is that one doesn't have to distinguish between
77different compilers for different languages (think <tt class="docutils literal"><span class="pre">g++</span></tt> vs. <tt class="docutils literal"><span class="pre">gcc</span></tt>) - the
78right toolchain is chosen automatically based on input language names (which
79are, in turn, determined from file extensions). If you want to force files
80ending with &quot;.c&quot; to compile as C++, use the <tt class="docutils literal"><span class="pre">-x</span></tt> option, just like you would
81do it with <tt class="docutils literal"><span class="pre">gcc</span></tt>:</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]82<pre class="literal-block">
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]83$ # hello.c is really a C++ file
84$ llvmc -x c++ hello.c
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]85$ ./a.out
86hello
87</pre>
88<p>On the other hand, when using LLVMC as a linker to combine several C++
89object files you should provide the <tt class="docutils literal"><span class="pre">--linker</span></tt> option since it's
90impossible for LLVMC to choose the right linker in that case:</p>
91<pre class="literal-block">
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]92$ llvmc -c hello.cpp
93$ llvmc hello.o
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]94[A lot of link-time errors skipped]
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]95$ llvmc --linker=c++ hello.o
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]96$ ./a.out
97hello
98</pre>
Mikhail Glushenkov7b366b52009-06-30 00:16:43 +0000[diff] [blame]99<p>By default, LLVMC uses <tt class="docutils literal"><span class="pre">llvm-gcc</span></tt> to compile the source code. It is also
100possible to choose the <tt class="docutils literal"><span class="pre">clang</span></tt> compiler with the <tt class="docutils literal"><span class="pre">-clang</span></tt> option.</p>
Reid Spencerd5c0ccb2004-08-09 03:08:29 +0000[diff] [blame]101</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]102<div class="section" id="predefined-options">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]103<h1><a class="toc-backref" href="#id10">Predefined options</a></h1>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]104<p>LLVMC has some built-in options that can't be overridden in the
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]105configuration libraries:</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]106<ul class="simple">
107<li><tt class="docutils literal"><span class="pre">-o</span> <span class="pre">FILE</span></tt> - Output file name.</li>
108<li><tt class="docutils literal"><span class="pre">-x</span> <span class="pre">LANGUAGE</span></tt> - Specify the language of the following input files
109until the next -x option.</li>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]110<li><tt class="docutils literal"><span class="pre">-load</span> <span class="pre">PLUGIN_NAME</span></tt> - Load the specified plugin DLL. Example:
111<tt class="docutils literal"><span class="pre">-load</span> <span class="pre">$LLVM_DIR/Release/lib/LLVMCSimple.so</span></tt>.</li>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]112<li><tt class="docutils literal"><span class="pre">-v</span></tt> - Enable verbose mode, i.e. print out all executed commands.</li>
Mikhail Glushenkov2b4a7dc2009-06-25 18:21:10 +0000[diff] [blame]113<li><tt class="docutils literal"><span class="pre">--save-temps</span></tt> - Write temporary files to the current directory and do not
114delete them on exit. This option can also take an argument: the
115<tt class="docutils literal"><span class="pre">--save-temps=obj</span></tt> switch will write files into the directory specified with
116the <tt class="docutils literal"><span class="pre">-o</span></tt> option. The <tt class="docutils literal"><span class="pre">--save-temps=cwd</span></tt> and <tt class="docutils literal"><span class="pre">--save-temps</span></tt> switches are
117both synonyms for the default behaviour.</li>
Mikhail Glushenkov0decbb22009-07-11 19:28:00 +0000[diff] [blame]118<li><tt class="docutils literal"><span class="pre">--temp-dir</span> <span class="pre">DIRECTORY</span></tt> - Store temporary files in the given directory. This
119directory is deleted on exit unless <tt class="docutils literal"><span class="pre">--save-temps</span></tt> is specified. If
120<tt class="docutils literal"><span class="pre">--save-temps=obj</span></tt> is also specified, <tt class="docutils literal"><span class="pre">--temp-dir</span></tt> is given the
121precedence.</li>
Mikhail Glushenkov0f78c272009-03-27 12:58:29 +0000[diff] [blame]122<li><tt class="docutils literal"><span class="pre">--check-graph</span></tt> - Check the compilation for common errors like mismatched
123output/input language names, multiple default edges and cycles. Because of
Mikhail Glushenkovb4b44ea2009-06-16 00:14:20 +0000[diff] [blame]124plugins, these checks can't be performed at compile-time. Exit with code zero
125if no errors were found, and return the number of found errors
126otherwise. Hidden option, useful for debugging LLVMC plugins.</li>
Mikhail Glushenkov0f78c272009-03-27 12:58:29 +0000[diff] [blame]127<li><tt class="docutils literal"><span class="pre">--view-graph</span></tt> - Show a graphical representation of the compilation graph
128and exit. Requires that you have <tt class="docutils literal"><span class="pre">dot</span></tt> and <tt class="docutils literal"><span class="pre">gv</span></tt> programs installed. Hidden
129option, useful for debugging LLVMC plugins.</li>
130<li><tt class="docutils literal"><span class="pre">--write-graph</span></tt> - Write a <tt class="docutils literal"><span class="pre">compilation-graph.dot</span></tt> file in the current
131directory with the compilation graph description in Graphviz format (identical
Mikhail Glushenkovb4b44ea2009-06-16 00:14:20 +0000[diff] [blame]132to the file used by the <tt class="docutils literal"><span class="pre">--view-graph</span></tt> option). The <tt class="docutils literal"><span class="pre">-o</span></tt> option can be
133used to set the output file name. Hidden option, useful for debugging LLVMC
134plugins.</li>
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]135<li><tt class="docutils literal"><span class="pre">-help</span></tt>, <tt class="docutils literal"><span class="pre">-help-hidden</span></tt>, <tt class="docutils literal"><span class="pre">--version</span></tt> - These options have
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]136their standard meaning.</li>
137</ul>
Reid Spencerd5c0ccb2004-08-09 03:08:29 +0000[diff] [blame]138</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]139<div class="section" id="compiling-llvmc-plugins">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]140<h1><a class="toc-backref" href="#id11">Compiling LLVMC plugins</a></h1>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]141<p>It's easiest to start working on your own LLVMC plugin by copying the
142skeleton project which lives under <tt class="docutils literal"><span class="pre">$LLVMC_DIR/plugins/Simple</span></tt>:</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]143<pre class="literal-block">
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]144$ cd $LLVMC_DIR/plugins
145$ cp -r Simple MyPlugin
146$ cd MyPlugin
147$ ls
148Makefile PluginMain.cpp Simple.td
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]149</pre>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]150<p>As you can see, our basic plugin consists of only two files (not
151counting the build script). <tt class="docutils literal"><span class="pre">Simple.td</span></tt> contains TableGen
152description of the compilation graph; its format is documented in the
153following sections. <tt class="docutils literal"><span class="pre">PluginMain.cpp</span></tt> is just a helper file used to
154compile the auto-generated C++ code produced from TableGen source. It
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]155can also contain hook definitions (see <a class="reference internal" href="#hooks">below</a>).</p>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]156<p>The first thing that you should do is to change the <tt class="docutils literal"><span class="pre">LLVMC_PLUGIN</span></tt>
157variable in the <tt class="docutils literal"><span class="pre">Makefile</span></tt> to avoid conflicts (since this variable
158is used to name the resulting library):</p>
159<pre class="literal-block">
160LLVMC_PLUGIN=MyPlugin
161</pre>
162<p>It is also a good idea to rename <tt class="docutils literal"><span class="pre">Simple.td</span></tt> to something less
163generic:</p>
164<pre class="literal-block">
165$ mv Simple.td MyPlugin.td
166</pre>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]167<p>To build your plugin as a dynamic library, just <tt class="docutils literal"><span class="pre">cd</span></tt> to its source
168directory and run <tt class="docutils literal"><span class="pre">make</span></tt>. The resulting file will be called
Mikhail Glushenkov7af1d242009-06-17 02:56:48 +0000[diff] [blame]169<tt class="docutils literal"><span class="pre">plugin_llvmc_$(LLVMC_PLUGIN).$(DLL_EXTENSION)</span></tt> (in our case,
170<tt class="docutils literal"><span class="pre">plugin_llvmc_MyPlugin.so</span></tt>). This library can be then loaded in with the
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]171<tt class="docutils literal"><span class="pre">-load</span></tt> option. Example:</p>
172<pre class="literal-block">
173$ cd $LLVMC_DIR/plugins/Simple
174$ make
Mikhail Glushenkov7af1d242009-06-17 02:56:48 +0000[diff] [blame]175$ llvmc -load $LLVM_DIR/Release/lib/plugin_llvmc_Simple.so
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]176</pre>
Mikhail Glushenkovb4b44ea2009-06-16 00:14:20 +0000[diff] [blame]177</div>
178<div class="section" id="compiling-standalone-llvmc-based-drivers">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]179<h1><a class="toc-backref" href="#id12">Compiling standalone LLVMC-based drivers</a></h1>
Mikhail Glushenkovb4b44ea2009-06-16 00:14:20 +0000[diff] [blame]180<p>By default, the <tt class="docutils literal"><span class="pre">llvmc</span></tt> executable consists of a driver core plus several
181statically linked plugins (<tt class="docutils literal"><span class="pre">Base</span></tt> and <tt class="docutils literal"><span class="pre">Clang</span></tt> at the moment). You can
182produce a standalone LLVMC-based driver executable by linking the core with your
183own plugins. The recommended way to do this is by starting with the provided
184<tt class="docutils literal"><span class="pre">Skeleton</span></tt> example (<tt class="docutils literal"><span class="pre">$LLVMC_DIR/example/Skeleton</span></tt>):</p>
185<pre class="literal-block">
186$ cd $LLVMC_DIR/example/
187$ cp -r Skeleton mydriver
188$ cd mydriver
189$ vim Makefile
190[...]
191$ make
192</pre>
193<p>If you're compiling LLVM with different source and object directories, then you
194must perform the following additional steps before running <tt class="docutils literal"><span class="pre">make</span></tt>:</p>
195<pre class="literal-block">
196# LLVMC_SRC_DIR = $LLVM_SRC_DIR/tools/llvmc/
197# LLVMC_OBJ_DIR = $LLVM_OBJ_DIR/tools/llvmc/
198$ cp $LLVMC_SRC_DIR/example/mydriver/Makefile \
199 $LLVMC_OBJ_DIR/example/mydriver/
200$ cd $LLVMC_OBJ_DIR/example/mydriver
201$ make
202</pre>
203<p>Another way to do the same thing is by using the following command:</p>
204<pre class="literal-block">
205$ cd $LLVMC_DIR
206$ make LLVMC_BUILTIN_PLUGINS=MyPlugin LLVMC_BASED_DRIVER_NAME=mydriver
207</pre>
Mikhail Glushenkov7af1d242009-06-17 02:56:48 +0000[diff] [blame]208<p>This works with both srcdir == objdir and srcdir != objdir, but assumes that the
Mikhail Glushenkovb4b44ea2009-06-16 00:14:20 +0000[diff] [blame]209plugin source directory was placed under <tt class="docutils literal"><span class="pre">$LLVMC_DIR/plugins</span></tt>.</p>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]210<p>Sometimes, you will want a 'bare-bones' version of LLVMC that has no
211built-in plugins. It can be compiled with the following command:</p>
212<pre class="literal-block">
213$ cd $LLVMC_DIR
Mikhail Glushenkovb4b44ea2009-06-16 00:14:20 +0000[diff] [blame]214$ make LLVMC_BUILTIN_PLUGINS=&quot;&quot;
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]215</pre>
216</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]217<div class="section" id="customizing-llvmc-the-compilation-graph">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]218<h1><a class="toc-backref" href="#id13">Customizing LLVMC: the compilation graph</a></h1>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]219<p>Each TableGen configuration file should include the common
220definitions:</p>
221<pre class="literal-block">
222include &quot;llvm/CompilerDriver/Common.td&quot;
223</pre>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]224<p>Internally, LLVMC stores information about possible source
225transformations in form of a graph. Nodes in this graph represent
226tools, and edges between two nodes represent a transformation path. A
227special &quot;root&quot; node is used to mark entry points for the
228transformations. LLVMC also assigns a weight to each edge (more on
229this later) to choose between several alternative edges.</p>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]230<p>The definition of the compilation graph (see file
231<tt class="docutils literal"><span class="pre">plugins/Base/Base.td</span></tt> for an example) is just a list of edges:</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]232<pre class="literal-block">
233def CompilationGraph : CompilationGraph&lt;[
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]234 Edge&lt;&quot;root&quot;, &quot;llvm_gcc_c&quot;&gt;,
235 Edge&lt;&quot;root&quot;, &quot;llvm_gcc_assembler&quot;&gt;,
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]236 ...
237
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]238 Edge&lt;&quot;llvm_gcc_c&quot;, &quot;llc&quot;&gt;,
239 Edge&lt;&quot;llvm_gcc_cpp&quot;, &quot;llc&quot;&gt;,
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]240 ...
241
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]242 OptionalEdge&lt;&quot;llvm_gcc_c&quot;, &quot;opt&quot;, (case (switch_on &quot;opt&quot;),
243 (inc_weight))&gt;,
244 OptionalEdge&lt;&quot;llvm_gcc_cpp&quot;, &quot;opt&quot;, (case (switch_on &quot;opt&quot;),
245 (inc_weight))&gt;,
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]246 ...
247
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]248 OptionalEdge&lt;&quot;llvm_gcc_assembler&quot;, &quot;llvm_gcc_cpp_linker&quot;,
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]249 (case (input_languages_contain &quot;c++&quot;), (inc_weight),
250 (or (parameter_equals &quot;linker&quot;, &quot;g++&quot;),
251 (parameter_equals &quot;linker&quot;, &quot;c++&quot;)), (inc_weight))&gt;,
252 ...
253
254 ]&gt;;
255</pre>
256<p>As you can see, the edges can be either default or optional, where
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]257optional edges are differentiated by an additional <tt class="docutils literal"><span class="pre">case</span></tt> expression
258used to calculate the weight of this edge. Notice also that we refer
259to tools via their names (as strings). This makes it possible to add
260edges to an existing compilation graph in plugins without having to
261know about all tool definitions used in the graph.</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]262<p>The default edges are assigned a weight of 1, and optional edges get a
263weight of 0 + 2*N where N is the number of tests that evaluated to
264true in the <tt class="docutils literal"><span class="pre">case</span></tt> expression. It is also possible to provide an
265integer parameter to <tt class="docutils literal"><span class="pre">inc_weight</span></tt> and <tt class="docutils literal"><span class="pre">dec_weight</span></tt> - in this case,
266the weight is increased (or decreased) by the provided value instead
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]267of the default 2. It is also possible to change the default weight of
268an optional edge by using the <tt class="docutils literal"><span class="pre">default</span></tt> clause of the <tt class="docutils literal"><span class="pre">case</span></tt>
269construct.</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]270<p>When passing an input file through the graph, LLVMC picks the edge
271with the maximum weight. To avoid ambiguity, there should be only one
272default edge between two nodes (with the exception of the root node,
273which gets a special treatment - there you are allowed to specify one
274default edge <em>per language</em>).</p>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]275<p>When multiple plugins are loaded, their compilation graphs are merged
276together. Since multiple edges that have the same end nodes are not
277allowed (i.e. the graph is not a multigraph), an edge defined in
278several plugins will be replaced by the definition from the plugin
279that was loaded last. Plugin load order can be controlled by using the
280plugin priority feature described above.</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]281<p>To get a visual representation of the compilation graph (useful for
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]282debugging), run <tt class="docutils literal"><span class="pre">llvmc</span> <span class="pre">--view-graph</span></tt>. You will need <tt class="docutils literal"><span class="pre">dot</span></tt> and
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]283<tt class="docutils literal"><span class="pre">gsview</span></tt> installed for this to work properly.</p>
Reid Spencerd5c0ccb2004-08-09 03:08:29 +0000[diff] [blame]284</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]285<div class="section" id="describing-options">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]286<h1><a class="toc-backref" href="#id14">Describing options</a></h1>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]287<p>Command-line options that the plugin supports are defined by using an
288<tt class="docutils literal"><span class="pre">OptionList</span></tt>:</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]289<pre class="literal-block">
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]290def Options : OptionList&lt;[
291(switch_option &quot;E&quot;, (help &quot;Help string&quot;)),
292(alias_option &quot;quiet&quot;, &quot;q&quot;)
293...
294]&gt;;
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]295</pre>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]296<p>As you can see, the option list is just a list of DAGs, where each DAG
297is an option description consisting of the option name and some
298properties. A plugin can define more than one option list (they are
299all merged together in the end), which can be handy if one wants to
300separate option groups syntactically.</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]301<ul>
302<li><p class="first">Possible option types:</p>
303<blockquote>
304<ul class="simple">
Mikhail Glushenkov84172f72009-01-28 03:47:38 +0000[diff] [blame]305<li><tt class="docutils literal"><span class="pre">switch_option</span></tt> - a simple boolean switch without arguments, for example
306<tt class="docutils literal"><span class="pre">-O2</span></tt> or <tt class="docutils literal"><span class="pre">-time</span></tt>. At most one occurrence is allowed.</li>
307<li><tt class="docutils literal"><span class="pre">parameter_option</span></tt> - option that takes one argument, for example
308<tt class="docutils literal"><span class="pre">-std=c99</span></tt>. It is also allowed to use spaces instead of the equality
309sign: <tt class="docutils literal"><span class="pre">-std</span> <span class="pre">c99</span></tt>. At most one occurrence is allowed.</li>
310<li><tt class="docutils literal"><span class="pre">parameter_list_option</span></tt> - same as the above, but more than one option
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]311occurence is allowed.</li>
Mikhail Glushenkov84172f72009-01-28 03:47:38 +0000[diff] [blame]312<li><tt class="docutils literal"><span class="pre">prefix_option</span></tt> - same as the parameter_option, but the option name and
313argument do not have to be separated. Example: <tt class="docutils literal"><span class="pre">-ofile</span></tt>. This can be also
314specified as <tt class="docutils literal"><span class="pre">-o</span> <span class="pre">file</span></tt>; however, <tt class="docutils literal"><span class="pre">-o=file</span></tt> will be parsed incorrectly
315(<tt class="docutils literal"><span class="pre">=file</span></tt> will be interpreted as option value). At most one occurrence is
316allowed.</li>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]317<li><tt class="docutils literal"><span class="pre">prefix_list_option</span></tt> - same as the above, but more than one occurence of
Mikhail Glushenkov84172f72009-01-28 03:47:38 +0000[diff] [blame]318the option is allowed; example: <tt class="docutils literal"><span class="pre">-lm</span> <span class="pre">-lpthread</span></tt>.</li>
319<li><tt class="docutils literal"><span class="pre">alias_option</span></tt> - a special option type for creating aliases. Unlike other
320option types, aliases are not allowed to have any properties besides the
321aliased option name. Usage example: <tt class="docutils literal"><span class="pre">(alias_option</span> <span class="pre">&quot;preprocess&quot;,</span> <span class="pre">&quot;E&quot;)</span></tt></li>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]322</ul>
323</blockquote>
324</li>
325<li><p class="first">Possible option properties:</p>
326<blockquote>
327<ul class="simple">
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]328<li><tt class="docutils literal"><span class="pre">help</span></tt> - help string associated with this option. Used for <tt class="docutils literal"><span class="pre">-help</span></tt>
Mikhail Glushenkov84172f72009-01-28 03:47:38 +0000[diff] [blame]329output.</li>
330<li><tt class="docutils literal"><span class="pre">required</span></tt> - this option must be specified exactly once (or, in case of
331the list options without the <tt class="docutils literal"><span class="pre">multi_val</span></tt> property, at least
332once). Incompatible with <tt class="docutils literal"><span class="pre">zero_or_one</span></tt> and <tt class="docutils literal"><span class="pre">one_or_more</span></tt>.</li>
333<li><tt class="docutils literal"><span class="pre">one_or_more</span></tt> - the option must be specified at least one time. Useful
334only for list options in conjunction with <tt class="docutils literal"><span class="pre">multi_val</span></tt>; for ordinary lists
335it is synonymous with <tt class="docutils literal"><span class="pre">required</span></tt>. Incompatible with <tt class="docutils literal"><span class="pre">required</span></tt> and
336<tt class="docutils literal"><span class="pre">zero_or_one</span></tt>.</li>
Mikhail Glushenkov108b0682009-12-17 07:49:26 +0000[diff] [blame]337<li><tt class="docutils literal"><span class="pre">optional</span></tt> - the option can be specified zero or one times. Useful only
338for list options in conjunction with <tt class="docutils literal"><span class="pre">multi_val</span></tt>. Incompatible with
Mikhail Glushenkov84172f72009-01-28 03:47:38 +0000[diff] [blame]339<tt class="docutils literal"><span class="pre">required</span></tt> and <tt class="docutils literal"><span class="pre">one_or_more</span></tt>.</li>
Mikhail Glushenkovbc39dff2009-01-15 02:42:40 +0000[diff] [blame]340<li><tt class="docutils literal"><span class="pre">hidden</span></tt> - the description of this option will not appear in
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]341the <tt class="docutils literal"><span class="pre">-help</span></tt> output (but will appear in the <tt class="docutils literal"><span class="pre">-help-hidden</span></tt>
Mikhail Glushenkovbc39dff2009-01-15 02:42:40 +0000[diff] [blame]342output).</li>
343<li><tt class="docutils literal"><span class="pre">really_hidden</span></tt> - the option will not be mentioned in any help
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]344output.</li>
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]345<li><tt class="docutils literal"><span class="pre">comma_separated</span></tt> - Indicates that any commas specified for an option's
346value should be used to split the value up into multiple values for the
347option. This property is valid only for list options. In conjunction with
348<tt class="docutils literal"><span class="pre">forward_value</span></tt> can be used to implement option forwarding in style of
349gcc's <tt class="docutils literal"><span class="pre">-Wa,</span></tt>.</li>
Mikhail Glushenkov84172f72009-01-28 03:47:38 +0000[diff] [blame]350<li><tt class="docutils literal"><span class="pre">multi_val</span> <span class="pre">n</span></tt> - this option takes <em>n</em> arguments (can be useful in some
351special cases). Usage example: <tt class="docutils literal"><span class="pre">(parameter_list_option</span> <span class="pre">&quot;foo&quot;,</span> <span class="pre">(multi_val</span>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]352<span class="pre">3))</span></tt>; the command-line syntax is '-foo a b c'. Only list options can have
Mikhail Glushenkov108b0682009-12-17 07:49:26 +0000[diff] [blame]353this attribute; you can, however, use the <tt class="docutils literal"><span class="pre">one_or_more</span></tt>, <tt class="docutils literal"><span class="pre">optional</span></tt>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]354and <tt class="docutils literal"><span class="pre">required</span></tt> properties.</li>
Mikhail Glushenkov54751922009-07-07 16:09:48 +0000[diff] [blame]355<li><tt class="docutils literal"><span class="pre">init</span></tt> - this option has a default value, either a string (if it is a
Mikhail Glushenkov108b0682009-12-17 07:49:26 +0000[diff] [blame]356parameter), or a boolean (if it is a switch; as in C++, boolean constants
357are called <tt class="docutils literal"><span class="pre">true</span></tt> and <tt class="docutils literal"><span class="pre">false</span></tt>). List options can't have <tt class="docutils literal"><span class="pre">init</span></tt>
358attribute.
359Usage examples: <tt class="docutils literal"><span class="pre">(switch_option</span> <span class="pre">&quot;foo&quot;,</span> <span class="pre">(init</span> <span class="pre">true))</span></tt>; <tt class="docutils literal"><span class="pre">(prefix_option</span>
360<span class="pre">&quot;bar&quot;,</span> <span class="pre">(init</span> <span class="pre">&quot;baz&quot;))</span></tt>.</li>
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]361<li><tt class="docutils literal"><span class="pre">extern</span></tt> - this option is defined in some other plugin, see <a class="reference internal" href="#extern">below</a>.</li>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]362</ul>
363</blockquote>
364</li>
365</ul>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]366<div class="section" id="external-options">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]367<span id="extern"></span><h2><a class="toc-backref" href="#id15">External options</a></h2>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]368<p>Sometimes, when linking several plugins together, one plugin needs to
369access options defined in some other plugin. Because of the way
Mikhail Glushenkovbc39dff2009-01-15 02:42:40 +0000[diff] [blame]370options are implemented, such options must be marked as
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]371<tt class="docutils literal"><span class="pre">extern</span></tt>. This is what the <tt class="docutils literal"><span class="pre">extern</span></tt> option property is
372for. Example:</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]373<pre class="literal-block">
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]374...
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]375(switch_option &quot;E&quot;, (extern))
376...
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]377</pre>
Mikhail Glushenkovff4718b2009-07-07 16:44:20 +0000[diff] [blame]378<p>If an external option has additional attributes besides 'extern', they are
379ignored. See also the section on plugin <a class="reference internal" href="#priorities">priorities</a>.</p>
Reid Spencerd5c0ccb2004-08-09 03:08:29 +0000[diff] [blame]380</div>
Reid Spencerd5c0ccb2004-08-09 03:08:29 +0000[diff] [blame]381</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]382<div class="section" id="conditional-evaluation">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]383<span id="case"></span><h1><a class="toc-backref" href="#id16">Conditional evaluation</a></h1>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]384<p>The 'case' construct is the main means by which programmability is
385achieved in LLVMC. It can be used to calculate edge weights, program
386actions and modify the shell commands to be executed. The 'case'
387expression is designed after the similarly-named construct in
388functional languages and takes the form <tt class="docutils literal"><span class="pre">(case</span> <span class="pre">(test_1),</span> <span class="pre">statement_1,</span>
389<span class="pre">(test_2),</span> <span class="pre">statement_2,</span> <span class="pre">...</span> <span class="pre">(test_N),</span> <span class="pre">statement_N)</span></tt>. The statements
390are evaluated only if the corresponding tests evaluate to true.</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]391<p>Examples:</p>
392<pre class="literal-block">
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]393// Edge weight calculation
394
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]395// Increases edge weight by 5 if &quot;-A&quot; is provided on the
396// command-line, and by 5 more if &quot;-B&quot; is also provided.
397(case
398 (switch_on &quot;A&quot;), (inc_weight 5),
399 (switch_on &quot;B&quot;), (inc_weight 5))
400
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]401
402// Tool command line specification
403
404// Evaluates to &quot;cmdline1&quot; if the option &quot;-A&quot; is provided on the
405// command line; to &quot;cmdline2&quot; if &quot;-B&quot; is provided;
406// otherwise to &quot;cmdline3&quot;.
407
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]408(case
409 (switch_on &quot;A&quot;), &quot;cmdline1&quot;,
410 (switch_on &quot;B&quot;), &quot;cmdline2&quot;,
411 (default), &quot;cmdline3&quot;)
412</pre>
413<p>Note the slight difference in 'case' expression handling in contexts
414of edge weights and command line specification - in the second example
415the value of the <tt class="docutils literal"><span class="pre">&quot;B&quot;</span></tt> switch is never checked when switch <tt class="docutils literal"><span class="pre">&quot;A&quot;</span></tt> is
416enabled, and the whole expression always evaluates to <tt class="docutils literal"><span class="pre">&quot;cmdline1&quot;</span></tt> in
417that case.</p>
418<p>Case expressions can also be nested, i.e. the following is legal:</p>
419<pre class="literal-block">
420(case (switch_on &quot;E&quot;), (case (switch_on &quot;o&quot;), ..., (default), ...)
421 (default), ...)
422</pre>
423<p>You should, however, try to avoid doing that because it hurts
424readability. It is usually better to split tool descriptions and/or
425use TableGen inheritance instead.</p>
426<ul class="simple">
427<li>Possible tests are:<ul>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]428<li><tt class="docutils literal"><span class="pre">switch_on</span></tt> - Returns true if a given command-line switch is provided by
429the user. Can be given a list as argument, in that case <tt class="docutils literal"><span class="pre">(switch_on</span> <span class="pre">[&quot;foo&quot;,</span>
430<span class="pre">&quot;bar&quot;,</span> <span class="pre">&quot;baz&quot;])</span></tt> is equivalent to <tt class="docutils literal"><span class="pre">(and</span> <span class="pre">(switch_on</span> <span class="pre">&quot;foo&quot;),</span> <span class="pre">(switch_on</span>
431<span class="pre">&quot;bar&quot;),</span> <span class="pre">(switch_on</span> <span class="pre">&quot;baz&quot;))</span></tt>.
432Example: <tt class="docutils literal"><span class="pre">(switch_on</span> <span class="pre">&quot;opt&quot;)</span></tt>.</li>
433<li><tt class="docutils literal"><span class="pre">any_switch_on</span></tt> - Given a list of switch options, returns true if any of
434the switches is turned on.
435Example: <tt class="docutils literal"><span class="pre">(any_switch_on</span> <span class="pre">[&quot;foo&quot;,</span> <span class="pre">&quot;bar&quot;,</span> <span class="pre">&quot;baz&quot;])</span></tt> is equivalent to <tt class="docutils literal"><span class="pre">(or</span>
436<span class="pre">(switch_on</span> <span class="pre">&quot;foo&quot;),</span> <span class="pre">(switch_on</span> <span class="pre">&quot;bar&quot;),</span> <span class="pre">(switch_on</span> <span class="pre">&quot;baz&quot;))</span></tt>.</li>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]437<li><tt class="docutils literal"><span class="pre">parameter_equals</span></tt> - Returns true if a command-line parameter equals
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]438a given value.
439Example: <tt class="docutils literal"><span class="pre">(parameter_equals</span> <span class="pre">&quot;W&quot;,</span> <span class="pre">&quot;all&quot;)</span></tt>.</li>
440<li><tt class="docutils literal"><span class="pre">element_in_list</span></tt> - Returns true if a command-line parameter
441list contains a given value.
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]442Example: <tt class="docutils literal"><span class="pre">(element_in_list</span> <span class="pre">&quot;l&quot;,</span> <span class="pre">&quot;pthread&quot;)</span></tt>.</li>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]443<li><tt class="docutils literal"><span class="pre">input_languages_contain</span></tt> - Returns true if a given language
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]444belongs to the current input language set.
445Example: <tt class="docutils literal"><span class="pre">(input_languages_contain</span> <span class="pre">&quot;c++&quot;)</span></tt>.</li>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]446<li><tt class="docutils literal"><span class="pre">in_language</span></tt> - Evaluates to true if the input file language is equal to
447the argument. At the moment works only with <tt class="docutils literal"><span class="pre">cmd_line</span></tt> and <tt class="docutils literal"><span class="pre">actions</span></tt> (on
448non-join nodes).
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]449Example: <tt class="docutils literal"><span class="pre">(in_language</span> <span class="pre">&quot;c++&quot;)</span></tt>.</li>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]450<li><tt class="docutils literal"><span class="pre">not_empty</span></tt> - Returns true if a given option (which should be either a
451parameter or a parameter list) is set by the user. Like <tt class="docutils literal"><span class="pre">switch_on</span></tt>, can
452be also given a list as argument.
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]453Example: <tt class="docutils literal"><span class="pre">(not_empty</span> <span class="pre">&quot;o&quot;)</span></tt>.</li>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]454<li><tt class="docutils literal"><span class="pre">any_not_empty</span></tt> - Returns true if <tt class="docutils literal"><span class="pre">not_empty</span></tt> returns true for any of
455the options in the list.
456Example: <tt class="docutils literal"><span class="pre">(any_not_empty</span> <span class="pre">[&quot;foo&quot;,</span> <span class="pre">&quot;bar&quot;,</span> <span class="pre">&quot;baz&quot;])</span></tt> is equivalent to <tt class="docutils literal"><span class="pre">(or</span>
457<span class="pre">(not_empty</span> <span class="pre">&quot;foo&quot;),</span> <span class="pre">(not_empty</span> <span class="pre">&quot;bar&quot;),</span> <span class="pre">(not_empty</span> <span class="pre">&quot;baz&quot;))</span></tt>.</li>
Mikhail Glushenkov0b9d8f82008-12-17 02:47:30 +0000[diff] [blame]458<li><tt class="docutils literal"><span class="pre">empty</span></tt> - The opposite of <tt class="docutils literal"><span class="pre">not_empty</span></tt>. Equivalent to <tt class="docutils literal"><span class="pre">(not</span> <span class="pre">(not_empty</span>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]459<span class="pre">X))</span></tt>. Provided for convenience. Can be given a list as argument.</li>
460<li><tt class="docutils literal"><span class="pre">any_not_empty</span></tt> - Returns true if <tt class="docutils literal"><span class="pre">not_empty</span></tt> returns true for any of
461the options in the list.
462Example: <tt class="docutils literal"><span class="pre">(any_empty</span> <span class="pre">[&quot;foo&quot;,</span> <span class="pre">&quot;bar&quot;,</span> <span class="pre">&quot;baz&quot;])</span></tt> is equivalent to <tt class="docutils literal"><span class="pre">(not</span> <span class="pre">(and</span>
463<span class="pre">(not_empty</span> <span class="pre">&quot;foo&quot;),</span> <span class="pre">(not_empty</span> <span class="pre">&quot;bar&quot;),</span> <span class="pre">(not_empty</span> <span class="pre">&quot;baz&quot;)))</span></tt>.</li>
Mikhail Glushenkov89cbdf02009-09-28 01:28:26 +0000[diff] [blame]464<li><tt class="docutils literal"><span class="pre">single_input_file</span></tt> - Returns true if there was only one input file
465provided on the command-line. Used without arguments:
466<tt class="docutils literal"><span class="pre">(single_input_file)</span></tt>.</li>
467<li><tt class="docutils literal"><span class="pre">multiple_input_files</span></tt> - Equivalent to <tt class="docutils literal"><span class="pre">(not</span> <span class="pre">(single_input_file))</span></tt> (the
468case of zero input files is considered an error).</li>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]469<li><tt class="docutils literal"><span class="pre">default</span></tt> - Always evaluates to true. Should always be the last
470test in the <tt class="docutils literal"><span class="pre">case</span></tt> expression.</li>
Mikhail Glushenkov89cbdf02009-09-28 01:28:26 +0000[diff] [blame]471<li><tt class="docutils literal"><span class="pre">and</span></tt> - A standard binary logical combinator that returns true iff all of
472its arguments return true. Used like this: <tt class="docutils literal"><span class="pre">(and</span> <span class="pre">(test1),</span> <span class="pre">(test2),</span>
473<span class="pre">...</span> <span class="pre">(testN))</span></tt>. Nesting of <tt class="docutils literal"><span class="pre">and</span></tt> and <tt class="docutils literal"><span class="pre">or</span></tt> is allowed, but not
474encouraged.</li>
475<li><tt class="docutils literal"><span class="pre">or</span></tt> - A binary logical combinator that returns true iff any of its
476arguments returns true. Example: <tt class="docutils literal"><span class="pre">(or</span> <span class="pre">(test1),</span> <span class="pre">(test2),</span> <span class="pre">...</span> <span class="pre">(testN))</span></tt>.</li>
477<li><tt class="docutils literal"><span class="pre">not</span></tt> - Standard unary logical combinator that negates its
478argument. Example: <tt class="docutils literal"><span class="pre">(not</span> <span class="pre">(or</span> <span class="pre">(test1),</span> <span class="pre">(test2),</span> <span class="pre">...</span> <span class="pre">(testN)))</span></tt>.</li>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]479</ul>
480</li>
481</ul>
Reid Spencera6288562004-08-22 18:06:59 +0000[diff] [blame]482</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]483<div class="section" id="writing-a-tool-description">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]484<h1><a class="toc-backref" href="#id17">Writing a tool description</a></h1>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]485<p>As was said earlier, nodes in the compilation graph represent tools,
486which are described separately. A tool definition looks like this
487(taken from the <tt class="docutils literal"><span class="pre">include/llvm/CompilerDriver/Tools.td</span></tt> file):</p>
488<pre class="literal-block">
489def llvm_gcc_cpp : Tool&lt;[
490 (in_language &quot;c++&quot;),
491 (out_language &quot;llvm-assembler&quot;),
492 (output_suffix &quot;bc&quot;),
493 (cmd_line &quot;llvm-g++ -c $INFILE -o $OUTFILE -emit-llvm&quot;),
494 (sink)
495 ]&gt;;
496</pre>
497<p>This defines a new tool called <tt class="docutils literal"><span class="pre">llvm_gcc_cpp</span></tt>, which is an alias for
498<tt class="docutils literal"><span class="pre">llvm-g++</span></tt>. As you can see, a tool definition is just a list of
499properties; most of them should be self-explanatory. The <tt class="docutils literal"><span class="pre">sink</span></tt>
500property means that this tool should be passed all command-line
501options that aren't mentioned in the option list.</p>
502<p>The complete list of all currently implemented tool properties follows.</p>
503<ul class="simple">
504<li>Possible tool properties:<ul>
505<li><tt class="docutils literal"><span class="pre">in_language</span></tt> - input language name. Can be either a string or a
506list, in case the tool supports multiple input languages.</li>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]507<li><tt class="docutils literal"><span class="pre">out_language</span></tt> - output language name. Multiple output languages are not
508allowed.</li>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]509<li><tt class="docutils literal"><span class="pre">output_suffix</span></tt> - output file suffix. Can also be changed
510dynamically, see documentation on actions.</li>
511<li><tt class="docutils literal"><span class="pre">cmd_line</span></tt> - the actual command used to run the tool. You can
512use <tt class="docutils literal"><span class="pre">$INFILE</span></tt> and <tt class="docutils literal"><span class="pre">$OUTFILE</span></tt> variables, output redirection
513with <tt class="docutils literal"><span class="pre">&gt;</span></tt>, hook invocations (<tt class="docutils literal"><span class="pre">$CALL</span></tt>), environment variables
514(via <tt class="docutils literal"><span class="pre">$ENV</span></tt>) and the <tt class="docutils literal"><span class="pre">case</span></tt> construct.</li>
515<li><tt class="docutils literal"><span class="pre">join</span></tt> - this tool is a &quot;join node&quot; in the graph, i.e. it gets a
516list of input files and joins them together. Used for linkers.</li>
517<li><tt class="docutils literal"><span class="pre">sink</span></tt> - all command-line options that are not handled by other
518tools are passed to this tool.</li>
519<li><tt class="docutils literal"><span class="pre">actions</span></tt> - A single big <tt class="docutils literal"><span class="pre">case</span></tt> expression that specifies how
520this tool reacts on command-line options (described in more detail
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]521<a class="reference internal" href="#actions">below</a>).</li>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]522</ul>
523</li>
524</ul>
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]525<div class="section" id="id5">
526<span id="actions"></span><h2><a class="toc-backref" href="#id18">Actions</a></h2>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]527<p>A tool often needs to react to command-line options, and this is
528precisely what the <tt class="docutils literal"><span class="pre">actions</span></tt> property is for. The next example
529illustrates this feature:</p>
530<pre class="literal-block">
531def llvm_gcc_linker : Tool&lt;[
532 (in_language &quot;object-code&quot;),
533 (out_language &quot;executable&quot;),
534 (output_suffix &quot;out&quot;),
535 (cmd_line &quot;llvm-gcc $INFILE -o $OUTFILE&quot;),
536 (join),
537 (actions (case (not_empty &quot;L&quot;), (forward &quot;L&quot;),
538 (not_empty &quot;l&quot;), (forward &quot;l&quot;),
539 (not_empty &quot;dummy&quot;),
540 [(append_cmd &quot;-dummy1&quot;), (append_cmd &quot;-dummy2&quot;)])
541 ]&gt;;
542</pre>
543<p>The <tt class="docutils literal"><span class="pre">actions</span></tt> tool property is implemented on top of the omnipresent
544<tt class="docutils literal"><span class="pre">case</span></tt> expression. It associates one or more different <em>actions</em>
545with given conditions - in the example, the actions are <tt class="docutils literal"><span class="pre">forward</span></tt>,
546which forwards a given option unchanged, and <tt class="docutils literal"><span class="pre">append_cmd</span></tt>, which
547appends a given string to the tool execution command. Multiple actions
548can be associated with a single condition by using a list of actions
549(used in the example to append some dummy options). The same <tt class="docutils literal"><span class="pre">case</span></tt>
550construct can also be used in the <tt class="docutils literal"><span class="pre">cmd_line</span></tt> property to modify the
551tool command line.</p>
552<p>The &quot;join&quot; property used in the example means that this tool behaves
553like a linker.</p>
554<p>The list of all possible actions follows.</p>
555<ul>
556<li><p class="first">Possible actions:</p>
557<blockquote>
558<ul class="simple">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]559<li><tt class="docutils literal"><span class="pre">append_cmd</span></tt> - Append a string to the tool invocation command.
560Example: <tt class="docutils literal"><span class="pre">(case</span> <span class="pre">(switch_on</span> <span class="pre">&quot;pthread&quot;),</span> <span class="pre">(append_cmd</span> <span class="pre">&quot;-lpthread&quot;))</span></tt>.</li>
561<li><tt class="docutils literal"><span class="pre">error</span></tt> - Exit with error.
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]562Example: <tt class="docutils literal"><span class="pre">(error</span> <span class="pre">&quot;Mixing</span> <span class="pre">-c</span> <span class="pre">and</span> <span class="pre">-S</span> <span class="pre">is</span> <span class="pre">not</span> <span class="pre">allowed!&quot;)</span></tt>.</li>
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]563<li><tt class="docutils literal"><span class="pre">warning</span></tt> - Print a warning.
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]564Example: <tt class="docutils literal"><span class="pre">(warning</span> <span class="pre">&quot;Specifying</span> <span class="pre">both</span> <span class="pre">-O1</span> <span class="pre">and</span> <span class="pre">-O2</span> <span class="pre">is</span> <span class="pre">meaningless!&quot;)</span></tt>.</li>
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]565<li><tt class="docutils literal"><span class="pre">forward</span></tt> - Forward the option unchanged.
566Example: <tt class="docutils literal"><span class="pre">(forward</span> <span class="pre">&quot;Wall&quot;)</span></tt>.</li>
567<li><tt class="docutils literal"><span class="pre">forward_as</span></tt> - Change the option's name, but forward the argument
568unchanged.
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]569Example: <tt class="docutils literal"><span class="pre">(forward_as</span> <span class="pre">&quot;O0&quot;,</span> <span class="pre">&quot;--disable-optimization&quot;)</span></tt>.</li>
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]570<li><tt class="docutils literal"><span class="pre">forward_value</span></tt> - Forward only option's value. Cannot be used with switch
571options (since they don't have values), but works fine with lists.
572Example: <tt class="docutils literal"><span class="pre">(forward_value</span> <span class="pre">&quot;Wa,&quot;)</span></tt>.</li>
573<li><tt class="docutils literal"><span class="pre">forward_transformed_value</span></tt> - As above, but applies a hook to the
574option's value before forwarding (see <a class="reference internal" href="#hooks">below</a>). When
575<tt class="docutils literal"><span class="pre">forward_transformed_value</span></tt> is applied to a list
576option, the hook must have signature
577<tt class="docutils literal"><span class="pre">std::string</span> <span class="pre">hooks::HookName</span> <span class="pre">(const</span> <span class="pre">std::vector&lt;std::string&gt;&amp;)</span></tt>.
578Example: <tt class="docutils literal"><span class="pre">(forward_transformed_value</span> <span class="pre">&quot;m&quot;,</span> <span class="pre">&quot;ConvertToMAttr&quot;)</span></tt>.</li>
579<li><tt class="docutils literal"><span class="pre">output_suffix</span></tt> - Modify the output suffix of this tool.
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]580Example: <tt class="docutils literal"><span class="pre">(output_suffix</span> <span class="pre">&quot;i&quot;)</span></tt>.</li>
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]581<li><tt class="docutils literal"><span class="pre">stop_compilation</span></tt> - Stop compilation after this tool processes its
582input. Used without arguments.
583Example: <tt class="docutils literal"><span class="pre">(stop_compilation)</span></tt>.</li>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]584</ul>
585</blockquote>
586</li>
587</ul>
588</div>
589</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]590<div class="section" id="language-map">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]591<h1><a class="toc-backref" href="#id19">Language map</a></h1>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]592<p>If you are adding support for a new language to LLVMC, you'll need to
593modify the language map, which defines mappings from file extensions
594to language names. It is used to choose the proper toolchain(s) for a
595given input file set. Language map definition looks like this:</p>
Anton Korobeynikov4167db92008-06-09 04:15:49 +0000[diff] [blame]596<pre class="literal-block">
597def LanguageMap : LanguageMap&lt;
598 [LangToSuffixes&lt;&quot;c++&quot;, [&quot;cc&quot;, &quot;cp&quot;, &quot;cxx&quot;, &quot;cpp&quot;, &quot;CPP&quot;, &quot;c++&quot;, &quot;C&quot;]&gt;,
599 LangToSuffixes&lt;&quot;c&quot;, [&quot;c&quot;]&gt;,
600 ...
601 ]&gt;;
602</pre>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]603<p>For example, without those definitions the following command wouldn't work:</p>
604<pre class="literal-block">
605$ llvmc hello.cpp
606llvmc: Unknown suffix: cpp
607</pre>
Mikhail Glushenkov108b0682009-12-17 07:49:26 +0000[diff] [blame]608<p>The language map entries are needed only for the tools that are linked from the
609root node. Since a tool can't have multiple output languages, for inner nodes of
610the graph the input and output languages should match. This is enforced at
611compile-time.</p>
Reid Spencera6288562004-08-22 18:06:59 +0000[diff] [blame]612</div>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]613<div class="section" id="option-preprocessor">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]614<h1><a class="toc-backref" href="#id20">Option preprocessor</a></h1>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]615<p>It is sometimes useful to run error-checking code before processing the
616compilation graph. For example, if optimization options &quot;-O1&quot; and &quot;-O2&quot; are
617implemented as switches, we might want to output a warning if the user invokes
618the driver with both of these options enabled.</p>
619<p>The <tt class="docutils literal"><span class="pre">OptionPreprocessor</span></tt> feature is reserved specially for these
620occasions. Example (adapted from the built-in Base plugin):</p>
621<pre class="literal-block">
622def Preprocess : OptionPreprocessor&lt;
Mikhail Glushenkov108b0682009-12-17 07:49:26 +0000[diff] [blame]623(case (not (any_switch_on [&quot;O0&quot;, &quot;O1&quot;, &quot;O2&quot;, &quot;O3&quot;])),
624 (set_option &quot;O2&quot;),
625 (and (switch_on &quot;O3&quot;), (any_switch_on [&quot;O0&quot;, &quot;O1&quot;, &quot;O2&quot;])),
626 (unset_option [&quot;O0&quot;, &quot;O1&quot;, &quot;O2&quot;]),
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]627 (and (switch_on &quot;O2&quot;), (any_switch_on [&quot;O0&quot;, &quot;O1&quot;])),
628 (unset_option [&quot;O0&quot;, &quot;O1&quot;]),
629 (and (switch_on &quot;O1&quot;), (switch_on &quot;O0&quot;)),
630 (unset_option &quot;O0&quot;))
631&gt;;
632</pre>
Mikhail Glushenkov108b0682009-12-17 07:49:26 +0000[diff] [blame]633<p>Here, <tt class="docutils literal"><span class="pre">OptionPreprocessor</span></tt> is used to unset all spurious <tt class="docutils literal"><span class="pre">-O</span></tt> options so
634that they are not forwarded to the compiler. If no optimization options are
635specified, <tt class="docutils literal"><span class="pre">-O2</span></tt> is enabled.</p>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]636<p><tt class="docutils literal"><span class="pre">OptionPreprocessor</span></tt> is basically a single big <tt class="docutils literal"><span class="pre">case</span></tt> expression, which is
637evaluated only once right after the plugin is loaded. The only allowed actions
Mikhail Glushenkov4429e702009-12-23 12:49:51 +0000[diff] [blame]638in <tt class="docutils literal"><span class="pre">OptionPreprocessor</span></tt> are <tt class="docutils literal"><span class="pre">error</span></tt>, <tt class="docutils literal"><span class="pre">warning</span></tt>, and two special actions:
Mikhail Glushenkov108b0682009-12-17 07:49:26 +0000[diff] [blame]639<tt class="docutils literal"><span class="pre">unset_option</span></tt> and <tt class="docutils literal"><span class="pre">set_option</span></tt>. As their names suggest, they can be used to
Mikhail Glushenkov4429e702009-12-23 12:49:51 +0000[diff] [blame]640set or unset a given option. To set an option with <tt class="docutils literal"><span class="pre">set_option</span></tt>, use the
641two-argument form: <tt class="docutils literal"><span class="pre">(set_option</span> <span class="pre">&quot;parameter&quot;,</span> <span class="pre">VALUE)</span></tt>. Here, <tt class="docutils literal"><span class="pre">VALUE</span></tt> can be
642either a string, a string list, or a boolean constant.</p>
643<p>For convenience, <tt class="docutils literal"><span class="pre">set_option</span></tt> and <tt class="docutils literal"><span class="pre">unset_option</span></tt> also work on lists. That
644is, instead of <tt class="docutils literal"><span class="pre">[(unset_option</span> <span class="pre">&quot;A&quot;),</span> <span class="pre">(unset_option</span> <span class="pre">&quot;B&quot;)]</span></tt> you can use
645<tt class="docutils literal"><span class="pre">(unset_option</span> <span class="pre">[&quot;A&quot;,</span> <span class="pre">&quot;B&quot;])</span></tt>. Obviously, <tt class="docutils literal"><span class="pre">(set_option</span> <span class="pre">[&quot;A&quot;,</span> <span class="pre">&quot;B&quot;])</span></tt> is valid
646only if both <tt class="docutils literal"><span class="pre">A</span></tt> and <tt class="docutils literal"><span class="pre">B</span></tt> are switches.</p>
Mikhail Glushenkov964020b2009-10-25 01:44:24 +0000[diff] [blame]647</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]648<div class="section" id="more-advanced-topics">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]649<h1><a class="toc-backref" href="#id21">More advanced topics</a></h1>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]650<div class="section" id="hooks-and-environment-variables">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]651<span id="hooks"></span><h2><a class="toc-backref" href="#id22">Hooks and environment variables</a></h2>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]652<p>Normally, LLVMC executes programs from the system <tt class="docutils literal"><span class="pre">PATH</span></tt>. Sometimes,
Mikhail Glushenkov84172f72009-01-28 03:47:38 +0000[diff] [blame]653this is not sufficient: for example, we may want to specify tool paths
654or names in the configuration file. This can be easily achieved via
655the hooks mechanism. To write your own hooks, just add their
656definitions to the <tt class="docutils literal"><span class="pre">PluginMain.cpp</span></tt> or drop a <tt class="docutils literal"><span class="pre">.cpp</span></tt> file into the
657your plugin directory. Hooks should live in the <tt class="docutils literal"><span class="pre">hooks</span></tt> namespace
658and have the signature <tt class="docutils literal"><span class="pre">std::string</span> <span class="pre">hooks::MyHookName</span> <span class="pre">([const</span> <span class="pre">char*</span>
659<span class="pre">Arg0</span> <span class="pre">[</span> <span class="pre">const</span> <span class="pre">char*</span> <span class="pre">Arg2</span> <span class="pre">[,</span> <span class="pre">...]]])</span></tt>. They can be used from the
660<tt class="docutils literal"><span class="pre">cmd_line</span></tt> tool property:</p>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]661<pre class="literal-block">
662(cmd_line &quot;$CALL(MyHook)/path/to/file -o $CALL(AnotherHook)&quot;)
663</pre>
Mikhail Glushenkov84172f72009-01-28 03:47:38 +0000[diff] [blame]664<p>To pass arguments to hooks, use the following syntax:</p>
665<pre class="literal-block">
666(cmd_line &quot;$CALL(MyHook, 'Arg1', 'Arg2', 'Arg # 3')/path/to/file -o1 -o2&quot;)
667</pre>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]668<p>It is also possible to use environment variables in the same manner:</p>
669<pre class="literal-block">
670(cmd_line &quot;$ENV(VAR1)/path/to/file -o $ENV(VAR2)&quot;)
671</pre>
672<p>To change the command line string based on user-provided options use
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]673the <tt class="docutils literal"><span class="pre">case</span></tt> expression (documented <a class="reference internal" href="#case">above</a>):</p>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]674<pre class="literal-block">
675(cmd_line
676 (case
677 (switch_on &quot;E&quot;),
678 &quot;llvm-g++ -E -x c $INFILE -o $OUTFILE&quot;,
679 (default),
680 &quot;llvm-g++ -c -x c $INFILE -o $OUTFILE -emit-llvm&quot;))
681</pre>
682</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]683<div class="section" id="how-plugins-are-loaded">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]684<span id="priorities"></span><h2><a class="toc-backref" href="#id23">How plugins are loaded</a></h2>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]685<p>It is possible for LLVMC plugins to depend on each other. For example,
686one can create edges between nodes defined in some other plugin. To
687make this work, however, that plugin should be loaded first. To
688achieve this, the concept of plugin priority was introduced. By
689default, every plugin has priority zero; to specify the priority
690explicitly, put the following line in your plugin's TableGen file:</p>
691<pre class="literal-block">
692def Priority : PluginPriority&lt;$PRIORITY_VALUE&gt;;
693# Where PRIORITY_VALUE is some integer &gt; 0
694</pre>
695<p>Plugins are loaded in order of their (increasing) priority, starting
696with 0. Therefore, the plugin with the highest priority value will be
697loaded last.</p>
698</div>
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]699<div class="section" id="debugging">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]700<h2><a class="toc-backref" href="#id24">Debugging</a></h2>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]701<p>When writing LLVMC plugins, it can be useful to get a visual view of
702the resulting compilation graph. This can be achieved via the command
Mikhail Glushenkov4707bf42009-05-06 01:41:47 +0000[diff] [blame]703line option <tt class="docutils literal"><span class="pre">--view-graph</span></tt>. This command assumes that <a class="reference external" href="http://www.graphviz.org/">Graphviz</a> and
704<a class="reference external" href="http://pages.cs.wisc.edu/~ghost/">Ghostview</a> are installed. There is also a <tt class="docutils literal"><span class="pre">--write-graph</span></tt> option that
Mikhail Glushenkovc0363fc2008-12-13 02:28:58 +0000[diff] [blame]705creates a Graphviz source file (<tt class="docutils literal"><span class="pre">compilation-graph.dot</span></tt>) in the
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]706current directory.</p>
Mikhail Glushenkovbc39dff2009-01-15 02:42:40 +0000[diff] [blame]707<p>Another useful <tt class="docutils literal"><span class="pre">llvmc</span></tt> option is <tt class="docutils literal"><span class="pre">--check-graph</span></tt>. It checks the
708compilation graph for common errors like mismatched output/input
709language names, multiple default edges and cycles. These checks can't
710be performed at compile-time because the plugins can load code
711dynamically. When invoked with <tt class="docutils literal"><span class="pre">--check-graph</span></tt>, <tt class="docutils literal"><span class="pre">llvmc</span></tt> doesn't
712perform any compilation tasks and returns the number of encountered
713errors as its status code.</p>
Mikhail Glushenkov7b366b52009-06-30 00:16:43 +0000[diff] [blame]714</div>
715<div class="section" id="conditioning-on-the-executable-name">
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]716<h2><a class="toc-backref" href="#id25">Conditioning on the executable name</a></h2>
Mikhail Glushenkov7b366b52009-06-30 00:16:43 +0000[diff] [blame]717<p>For now, the executable name (the value passed to the driver in <tt class="docutils literal"><span class="pre">argv[0]</span></tt>) is
718accessible only in the C++ code (i.e. hooks). Use the following code:</p>
719<pre class="literal-block">
720namespace llvmc {
721extern const char* ProgramName;
722}
723
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]724namespace hooks {
725
Mikhail Glushenkov7b366b52009-06-30 00:16:43 +0000[diff] [blame]726std::string MyHook() {
727//...
728if (strcmp(ProgramName, &quot;mydriver&quot;) == 0) {
729 //...
730
731}
Mikhail Glushenkov0bdfb532009-12-07 18:26:24 +0000[diff] [blame]732
733} // end namespace hooks
Mikhail Glushenkov7b366b52009-06-30 00:16:43 +0000[diff] [blame]734</pre>
735<p>In general, you're encouraged not to make the behaviour dependent on the
736executable file name, and use command-line switches instead. See for example how
737the <tt class="docutils literal"><span class="pre">Base</span></tt> plugin behaves when it needs to choose the correct linker options
738(think <tt class="docutils literal"><span class="pre">g++</span></tt> vs. <tt class="docutils literal"><span class="pre">gcc</span></tt>).</p>
Mikhail Glushenkov6932e2f2008-12-11 23:43:14 +0000[diff] [blame]739<hr />
Anton Korobeynikov2a67ecb2008-06-09 04:17:51 +0000[diff] [blame]740<address>
Mikhail Glushenkovc0363fc2008-12-13 02:28:58 +0000[diff] [blame]741<a href="http://jigsaw.w3.org/css-validator/check/referer">
742<img src="http://jigsaw.w3.org/css-validator/images/vcss-blue"
743 alt="Valid CSS" /></a>
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746 alt="Valid XHTML 1.0 Transitional"/></a>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]747
Mikhail Glushenkovc0363fc2008-12-13 02:28:58 +0000[diff] [blame]748<a href="mailto:foldr@codedgers.com">Mikhail Glushenkov</a><br />
749<a href="http://llvm.org">LLVM Compiler Infrastructure</a><br />
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]750
Duncan Sands142b9ed2010-02-18 14:08:13 +0000[diff] [blame]751Last modified: $Date$
Mikhail Glushenkovc0363fc2008-12-13 02:28:58 +0000[diff] [blame]752</address></div>
Mikhail Glushenkov6fd55132008-12-11 23:24:40 +0000[diff] [blame]753</div>
754</div>
Reid Spencerd5c0ccb2004-08-09 03:08:29 +0000[diff] [blame]755</body>
756</html>